It was not a terribly good day for China.

Both the men and women lost as the Cathay Pacific HSBC Hong Kong Rugby Sevens got underway on Friday at Hong Kong Stadium.

The men jumped out to an early lead in their opening match before falling to Tonga, 33-12.

Captain Li Jialin put China on the board in spectacular fashion less than a minute in, kicking the ball of a pair of Tonga players, then making a diving catch off the ricochet to score.

But it was all Tonga the rest of the way, as a rusty Chinese team struggled with its tackling.

China hadn't played a match in four months, said coach Johnny Zhang.

"On the defensive side, there aren't many people playing in China, so there's not enough opportunities and it's hard to practice their tackling skills.

"When we catch the ball and move forward, I think we were very good, but we weren't able to seize our opportunities and we made too many mistakes."

The women also had a rough night, losing to Spain, 12-7, in the women's Challenge Cup.

Barbara Pla scored early on a long breakaway run for Spain. Yang Hong scored on a pass from Sun Tingting just before halftime to tie it up, but Patricia Garcia sealed the victory in the second half.

The men will finish up pool play today with matches against Uruguay and Hong Kong. Zhang said he expects things to go a little better now what his team has a match under its belt.

"We regarded the match with Tonga as a warmup (after the long  hiatus),"  he said. "We did see a lot of problems we can improve on."